Determining network availability based on geographical location

ABSTRACT

A mobile terminal comprising: a positioning module arranged to determine a geographical location of the mobile terminal; a local transceiver for connecting to local wireless access networks; and processing apparatus for communicating with a first, packet-based network by forming connections with the wireless local area networks using the local transceiver. The processing apparatus is configured to determine measures of connection quality experienced by the mobile terminal on ones of the connections, and to record the determined measures in a database associating measures of connection quality with geographical locations. The processing apparatus is further configured to control activation of the local transceiver to scan for subsequent availability of one or more of the wireless local area networks, in dependence on one or more of the measures of connection quality and associated geographical locations in the database relative to the geographical location of the mobile terminal as determined by the positioning module.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/668,116, filed 2 Nov. 2012 which claims priority under 35 USC 119 or365 to Great Britain Application No. 1211568.9 filed 29 Jun. 2012, thedisclosure of which is incorporated in its entirety.

BACKGROUND

Some communication systems allow the user of a mobile terminal toconduct voice or video calls over a packet-based computer network, e.g.over an internetwork such as the Internet. Such communication systemsinclude voice or video over internet protocol (VoIP) systems. Thesesystems are beneficial to the user as they are often of significantlylower cost than conventional fixed-line or mobile networks, particularlyfor long-distance communication. Other types of communication media thatcan be implemented over a packet-based network include instant messaging(“IM”), SMS messaging, file transfer and/or voicemail.

When conducting communications such as VoIP calls over a first,packet-based network like the Internet, a mobile terminal typicallyconnects to the Internet via a second, access network (which may also bepacket-based in nature). If available, it is often possible to selectbetween multiple different access networks. Typically a mobile terminalhas two different types of connections available: Wireless Local AreaNetwork (WLAN) and Wireless Wide Area Network (WWAN). Many WLANstypically use wi-fi, but other local, short-range wireless standards arealso known in the art. The WWAN can be implemented by a number ofdifferent technologies such as GPRS, UMTS, HDPA, LTE, Wimax, etc.Usually, the type of WWAN available is decided by the operator, and assuch the decision to make at the mobile terminal boils down to whetherto use WLAN, WWAN, or both. On top of WLAN and WWAN, certain mobileterminals may have access to a satellite link as a third accesstechnology, though this is usually a “last resort” if neither WLAN norWWAN is accessible. In some systems it may also be possible to take intoaccount a users' physical location in deciding whether to move to anetwork connection using a different wireless internet accesstechnology.

To be able to choose which network to connect to, e.g. to select betweenWLAN or WWAN, or to select between two or more overlapping WLANs, themobile terminal needs to know which networks are physically present andin operation. To do this the mobile terminal powers up its wirelessinterface or interfaces and listens for paging signals from thenetworks. So if a mobile terminal comprises a short-range, localtransceiver for communicating with a local area wireless network such asa wi-fi network, this must be powered-up to listen for paging signalsbroadcast from any available WLANs; and if the mobile terminal comprisesa longer-range transceiver for communicating with a wide area wirelessnetwork such as a 3G or LTE network, this must be power-up to listen forpaging signals from the user's one or more WWAN providers. The interfaceis then powered down after a certain listening duration. This kind ofprocess may be referred herein to as a scan. Conventionally such scansare performed periodically, e.g. every few seconds or minutes, so thatthe mobile terminal always knows roughly what networks are available.

SUMMARY

According to embodiments of the present invention there is provided amobile terminal for use in a communication system comprising a first,packet-based network and a plurality of wireless local area networksproviding access to the first network. The mobile terminal comprises: apositioning module arranged to determine a geographical location of themobile terminal; a local transceiver for connecting to the localwireless access networks; and processing apparatus coupled to the localtransceiver and positioning system, operable to communicate with thefirst network by forming connections with the wireless local areanetworks using the local transceiver. The processing apparatus isconfigured to determine measures of connection quality experienced bythe mobile terminal on ones of said connections, and to record thedetermined measures in a database associating measures of connectionquality with geographical locations. The processing apparatus is furtherconfigured to control activation of the local transceiver to scan forsubsequent availability of one or more of the wireless local areanetworks, in dependence on one or more of the measures of connectionquality and associated geographical locations in said database relativeto the geographical location of the mobile terminal as determined bysaid positioning module.

According further embodiments of the present invention, there isprovided a corresponding method and computer program product.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Nor is theclaimed subject matter limited to implementations that solve any or allof the disadvantages noted in the Background section.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the various embodiments and to show how itmay be put into effect, reference is made by way of example to theaccompanying drawings in which:

FIG. 1 is a schematic representation of a communication system,

FIG. 2 is a schematic representation of a localization database,

FIG. 3 is a schematic representation of another localization database,

FIG. 4 is a schematic representation of another localization database,

FIG. 5 is a schematic representation of a cell-like localization scheme,and

FIG. 6 is a schematic representation of another localization database.

DETAILED DESCRIPTION

As mentioned, a mobile terminal performs a scan by powering up itswireless interface or interfaces and listening for paging signals frompotential networks in order to determine which networks are present. Themobile terminal can thereby choose which network to connect to (e.g. toselect between WLAN or WWAN, or between two or more overlapping WLANs).

One issue is that the scanning consumes a certain amount of power due tothe need to regularly power-up the relevant interface, and therefore theprocess can affect the battery life of the mobile terminal. In oneexisting system a location service server (LSS) tells the mobileterminal which networks are believed to be available based ongeographical location of the mobile in relation to known geographicinformation regarding network coverage. However, it is still necessaryto scan to determine whether the expected networks are actuallyavailable (the LSS contains only predetermined information and so cannotknow whether a network that was available historically is still in placeand working at the present time). Further, the LSS needs to be centrallymanaged and maintained by an operator, which is not always practicalfrom a logistical perspective. The LSS may take into account Quality ofService (QoS) information, like latency, packet loss and bandwidth.However, in the existing system this information is measured by themobile terminal in real-time, each time it considers handover, which maynot necessarily be practical in terms of the mobile terminal's resourceusage.

It would be desirable to find an improved way of determining whennetworks are likely to be available, so as to determine when to spendbattery power on performing scans for WLAN networks.

The various embodiments provide a mobile terminal for use in acommunication system comprising a first, packet-based network and aplurality of wireless local area networks providing access to the firstnetwork. The mobile terminal comprises a positioning module arranged todetermine a geographical location of the mobile terminal, a localtransceiver for connecting to the local wireless access networks, andprocessing apparatus coupled to the local transceiver and positioningsystem, operable to communicate with the first network by formingconnections with the wireless local area networks using the localtransceiver. The processing apparatus is configured to determinemeasures of connection quality experienced by the mobile terminal onones of the connections, and to record the determined measures in adatabase associating measures of connection quality with geographicallocations. The processing apparatus is further configured to controlactivation of the local transceiver to scan for subsequent availabilityof one or more of the wireless local area networks, in dependence on oneor more of the measures of connection quality and associatedgeographical locations in the database, relative to the geographicallocation of the mobile terminal as determined by the positioning module.Various embodiments can be implemented by way of a computer programproduct comprising code embodied on a computer-readable hardware storagemedium. “Computer-readable hardware storage medium” is intended to coverall statutory forms of computer-readable media. Accordingly,“computer-readable hardware storage medium” is not intended to covernon-statutory forms of media, e.g., signals or carrier waves.

The various embodiments thus enable one or more user terminals todynamically contribute to a database associating connection quality withgeographic location based on their actual experience. Thus the variousembodiments can reduce the need to scan when new networks are unlikelyto be available. Because the quality measures are stored in the databasein association with geographical locations, the mobile terminal does notnecessarily need to determine a new measure of quality each and everytime it considers whether scanning is worthwhile; but also, because thequality measures are contributed by the mobile terminal based on itspast experience, this is advantageously achieved without the need forthe database to be maintained solely by a central operator.

The below-described embodiments revolve around improving the experienceof a VoIP user by means of geographical localization data. In thevarious embodiments such information is used to enable selection of thebest network to connect to in a given scenario. The idea is to take intoaccount a users' physical location in deciding whether to move orattempt to move a network connection to a different wireless internetaccess technology.

As the mobile terminal moves to a new position, it performs a tablelook-up to see whether a network access point is available. In certainembodiments the table can be stored locally, with updates being pushednow and then. If an access point is nearby, a scan is triggered or thefrequency of scans is increased. This is advantageous over constantscanning which costs battery.

The method is further augmented according to one or more of thefollowing scenarios. In the following it is assumed that the user'sposition is known for example through GPS or other alternativepositioning techniques that will be discussed later.

A first scenario comprises a handover to a dynamically tagged accesspoint, based on storing and utilizing a history of different networks'quality indexed by localization. At the mobile, a table of data isstored comprising entries like {position, network, quality,time-of-day}. The quality parameter may comprise a measure of fidelity,such as signal strength or uplink and/or downlink bandwidth experiencedon the network. The table is updated when a call or similar is carriedout. When moving to a new position, the mobile terminal performs alook-up in this table to see whether there should be a better networkavailable at the current position. If so, it triggers a scan, orincreases the frequency of scans, and makes the handover if possible.This will save battery, and moreover void handovers to networks thatperformed poorly in the past.

A second scenario comprises a handover to a global dynamically taggedaccess point, based on dynamically updating and consulting a centralizedtable of network qualities indexed by localization. As a variant of theabove, the table could be kept at a server. All users then update thetable when trying out new networks and a user moving to a new positionperforms the look-up in the table on the server instead of locally. Thishas advantages over the locally tagged version as users learn from eachother, although it comes at the cost of increased radio access.

A third scenario comprises tagging networks with reliability parameters.The “quality” entry of a tagged network may alternatively oradditionally contain parameters describing reliability, for example, theaverage duration of uninterrupted service.

In an embodiment, quality is an aggregation of latency, bandwidth,reliability, loss and jitter. Alternatively the quality may comprise anyor all of these properties.

A fourth example comprises tagging networks with movement data, e.g. asbeing stationary or not. Stationary networks may be used when a user isstationary and vice versa. Certain WLAN access points (APs) arephysically moving. For example, this is true for on-board car or trainWLANs. This could be detected and stored in the dynamic taggingdatabase. A moving user would probably want to connect to such a movingaccess point, whereas a stationary user would not want to connect to,for example, an access point that is just passing by.

If a velocity estimate (speed and direction) is available, it is alsopossible to predict which network will become available and which willbe disconnected in the near future. This can be exploited. For example:in one direction of motion the best decision will be to handoff fromWLAN to WWAN, while in another direction of motion the best decisionwill be to handoff from current WLAN directly to the neighbour WLAN soas to avoid superfluous WLAN to WWAN to WLAN handover cycle.

A fifth scenario comprises rating providers as part of a virtualmarketplace, presenting to a user a list of available networks alongwith their quality as experienced by other users, or alternativelyselecting a network for the user based on pricing information, quality,user needs and/or activity. As an extension to the globally taggedaccess points, or an alternative, the user may be presented with hiscurrent connection options along with quality indicators and alsopricing information to help him select an appropriate one.Alternatively, the mobile terminal may make the decision for the userautomatically based on pricing info and what he is doing (e.g. audio orvideo call), and on a selection policy which can be either a default oneor one defined or selected by the user.

A sixth scenario involves reducing network scanning frequency when notmoving. When staying in the same position for a long time the frequencyof WLAN scanning can be reduced as the chance of (a better) one suddenlybecoming available is small. This saves battery. Further, instead ofconsulting the GPS which is costly battery wise, lack of movement couldbe detected via an accelerometer.

This idea can be extended to reduce network scanning frequency whenmoving fast.

Under certain conditions, for example when driving a car, constantscanning for WLANs is pointless and a waste of battery; WWAN is a betterchoice of connection. Such scenarios could be detected by consideringthe velocity data that are already present in typical GPS processingalgorithms.

Similarly, when already connected to a WLAN and moving at the same time(for example on a train or airplane) the frequency of WLAN scans can bereduced as the chance of one becoming available is very slim. Also, ifthe speed of travel is high it indicates we should not handover to WWANas that will lead to frequent cell handovers.

Hence network scanning frequency can be set in dependence of speed ofmovement. Scanning can be disabled when speed is too high.

In embodiments, a particularly preferred behavior with which a mobileterminal may be configured is to detect when the terminal is firstmoving and then subsequently stops. This may be taken to indicatearrival at a new position. Here it is particularly advantageous to scanfor new networks. Therefore the mobile terminal may advantageously beconfigured with a rule along the lines “trigger scan if not moving afterscans have been suspended due to motion”.

The above scenarios fall into two categories: firstly, localizationassisted network handovers by dynamic tagging, and secondly adaptationof network scanning to user movement.

Some examples of localization technologies that can be used to implementthe various embodiments are now discussed.

A first example is GPS. There are various ways to obtain theabove-mentioned localization data, such as GPS (the term GPS may be usedherein for all similar services, that is, it includes GLONASS andGalileo). Using such a system readily provides geocentric coordinates,velocity, and their associated uncertainties as long as the mobileterminal has a clear view to the sky. If accelerometer data isavailable, it can be incorporated as an acceleration observation, e.g.which fits into a Kalman filtering framework.

One problem with using GPS though is that it is quite battery hungry,but some of the scenarios above do not need continual positionmonitoring, i.e. the GPS could be turned on only when needed. In oldersystems, this might not have been a desirable option because obtainingthe position from cold start could take up to 12 minutes (broadcastcycle for almanac and ephemeris). However this problem has been relievedby assisted GPS (A-GPS) where information is received via a datanetwork.

Another option for obtaining geocentric-type coordinates is to observewhich network cells are available, based on cell ID. Combining this witha database will provide a rough location estimate. Such can be refinedby also taking into account signal strength. There are well-knowntrilateration methods for this. As compared to GPS such an approach ismuch less battery hungry and it works indoors. On the downside, it isnot as precise, and it works only in areas that have cell coverage.Obtaining velocity estimates should be possible just as for GPS, thoughthey will be less precise.

Another option is to use an ID of a nearby wi-fi access point ornetwork. WLAN networks have small coverage and therefore simplyobserving a nearby wi-fi access point is a good location indicator. Ifthe position of the wi-fi access point is known, this location can bedirectly mapped to coordinate data. Over time, a database of wi-fiaccess point locations can be built when they are observed and themobile terminal's location is known (for example, if GPS is running).

In some implementations of the above scenarios however, there may belittle need to map wi-fi IDs to geographical positions. Instead, analternative is to use the wi-fi ID for table lookup directly.

While this method cannot provide any meaningful velocity vectors, thespeed of movement can be assessed qualitatively by monitoring the rateof change of available wi-fi IDs.

Aggregated localization techniques may also be used, i.e. combiningdifferent localization techniques. For example the Skyhook and Place Labsystems make use of GPS, cell and wi-fi ID.

Some exemplary embodiments are now discussed in more detail in relationto FIG. 1.

FIG. 1 is a schematic illustration of a communication system 100comprising a plurality of communication networks. The plurality ofnetworks comprises a first, packet-switched network 101; in thisexample, a predominantly-wired, wide area internetwork such as theInternet. Connected to the first network 101, the plurality of networksfurther comprises at least one wireless wide area network (WWAN) and aplurality of wireless local area networks (WLANs).

The at least one WWAN comprises a mobile cellular network 103. Themobile cellular network 103 comprises a plurality of base stations 104(sometimes referred to as node Bs in 3GPP terminology) operatingaccording to a longer range wireless access technology. Each basestation 104 is arranged to serve a corresponding cell of the cellularnetwork 103.

Each of the WLANs comprises one or more local, short-range wirelessaccess points 106 such as wi-fi access points operating according to ashorter range wireless access technology. In some cases, a WLAN may beformed of only a single access point 106 (and whatever mobile userterminals are connected to it at the time).

WLAN and WWAN are terms that will be familiar to a person skilled in theart. A wireless local area connection uses a different kind of radiotechnology than a wireless wide area connection.

In most territories, local area wireless technologies are configured tooperate on unlicensed frequency bands whereas wide area wirelesstechnologies are configured to operate on licensed frequency bands.

Further, local area technologies are designed to form short-rangeconnections over a range of the order of tens of meters, e.g. eachaccess point covering a radius smaller than about 100 m or 200 m. Forexample a WLAN is typically arranged to cover a region corresponding tothe size of a room, building, office, shop, cafe or such like. Wide areatechnologies on the other hand are designed to form connections over arange of the order of hundreds of meters or kilometers, e.g. each basestation covering a cell of radius greater than 200 m, 500 m or 1 km. Forexample a cell is typically arranged to cover a region corresponding tothe size of several streets or a village, and the network itself isarranged to cover a region corresponding to the size of a town, city,county, state or country or even crossing boundaries between countries.

Examples of WWANs include LTE (Long Term Evolution), W-CDMA (WidebandCode Division Multiple Access), GSM (Global System for MobileCommunications), UMTS (Universal Mobile Telecommunications System),UTRAN (Universal Terrestrial Radio Access Network), HSPA (High SpeedPacket Access), CDMA2000 or other 3GPP (3^(rd) Generation PartnershipProject) networks; WiMAX networks, CDPD (Cellular Digital Packet Data)networks and Mobitex networks. Other WWAN technologies may be familiarto a person skilled in the art.

Examples of WLANs include wi-fi networks, a HiperLAN networks, HomeRFnetworks, OpenAir networks and Bluetooth networks. Other WLANtechnologies may be familiar to a person skilled in the art.

For illustrative purposes, the following will be described in terms of a3G network and a plurality of wi-fi networks providing access to theinternet 101, but it will be appreciated that the teachings herein canapply to any one or more wide area wireless networks and any local areawireless networks for providing access to any further packet-basednetwork, in this example, a predominantly-wired wide area internetwork.

Still referring to FIG. 1, a plurality of mobile user terminals 102 arearranged to communicate over the networks 101, 103 and/or 106. The userterminals 102 may comprise for example laptop computers, tablets orother mobile terminals such as mobile phones. Each user terminal 102comprises one or more transceivers for accessing the one or morenetworks 101, 103, 106.

Each user terminal 102 comprises a short-range wireless transceiver(e.g. wi-fi) for accessing the Internet 101 via the wireless accesspoints 106. In some places, a WLAN may be formed of a single short-rangeaccess point 106. In other places, small numbers of access points 106may be connected together to form a WLAN connecting to the internet 101through shared local area network equipment. Either way, a mobileterminal 102 connecting to one of the local access points 106 isprovided with a route for accessing the internet 101.

Further, each user terminal 102 typically comprises a cellular wirelesstransceiver 114 for accessing the mobile cellular network 103 via thebase stations 104. Access to the Internet 101 may be achieved by meansof the base stations 104 of the cellular WWAN 103, e.g. using a mobilepacket technology such as GPRS (General Packet Radio Service) or HSPA(High Speed Packet Access). At a higher level of the cellular hierarchy,the cellular network 103 comprises a plurality of cellular controllerstations 105 each coupled to a plurality of the base stations 104. Thecontroller stations 105 are coupled to a traditional circuit-switchedportion of the mobile cellular network 103 but also to the Internet 101.The controller stations 105 are thus arranged to allow access topacket-based communications via the base stations 104, including accessto the Internet 101. The controller stations 105 may be referred to forexample as Base Station Controllers (BSCs) in GSM/EDGE terminology, orRadio Network Controllers (RNCs) in USTM or HSPA terminology.

As mentioned, the cellular and short-range wireless transceivers aretypically arranged to operate on radio frequencies (RF), with thecellular wireless transceiver 114 typically being arranged to operate ona licensed RF band and the short-range wireless transceiver 115 beingarranged to operate on an unlicensed RF band.

An alternative or additional WWAN that may be available in some systemsis provided by satellite hub 109 connected to the internet 101. Thesatellite WWAN may provide yet another route enabling the mobileterminal 102 to access the internet 101 via a satellite transceiver ofthe mobile terminal 102, typically as a back-up if the other routes viathe cellular WWAN or the LLANs fail or are unavailable.

Each user terminal 102 further comprises a memory 110 such as anelectronic erasable and programmable memory (EEPROM, or “flash” memory);and a processor 112 coupled to the memory 110, cellular wirelesstransceiver 114 and short-range wireless transceiver 115. The memory 110stores communications code arranged to be executed on the processor 112,and configured so as when executed to engage in communications over theInternet 101 and/or cellular network 103. The communications code maycomprise signal processing code for transmitting and receiving signalsover the wireless cellular network 103 via the cellular wirelesstransceiver 114 (and/or some or all of this functionality may beimplemented in the cellular transceiver 114, though the increasing trendis for at least some of the signal processing to be performed insoftware). Further, the communications code comprises a communicationclient application for performing communications such as voice or videocalls with other user terminals 102 over the Internet 103, via theshort-range wireless transceiver 115 and wireless access points 106;and/or via the cellular wireless transceiver 114, base stations 104 andcontroller stations 105 of the cellular network 103 as discussed above.However, one or more of the user terminals 102 involved couldalternatively communicate via a wired modem, e.g. in the case of a callbetween a mobile terminal and a desktop PC.

At least some of the user terminals 102 are additionally equipped with apositioning system, coupled to the processor 112. In embodiments thistakes the form of a satellite-based positioning system 113 such as a GPSreceiver (possibly including of the assisted GPS feature), configured todetect the geographical location of its respective user terminal 102 byreference to a plurality of satellites 107 according to techniques knownin the art (usually not the same satellites as provide the back-upinternet access via hub 109, though at least some of the components ofthe satellite transceiver 113 may be shared). In the case of GPS, thesystem 113 returns a set of geographic coordinates, for example in theform of a pair of latitude and longitude values such as WGS84 (WorldGeodic System 1984) coordinates of the form (e.g. 51.0000, 0.5200).

In other embodiments, the positioning system could alternatively oradditionally comprise a cellular positioning system in the form ofcellular positioning code stored on the memory 110 and arranged forexecution on the processor 112. In that case, the cellular positioningcode is arranged to detect the location of the user terminal 102 byreference to one or more base stations 104. This can be achieved crudelyby identifying the location of the base station 104 which is currentlyserving the user terminal 102, or more accurately by identifying thelocation of a plurality of nearby base stations 104 and performing atrilateration. In the latter case, the trilateration works by detectingthe time for a signal to travel between the user terminal 102 and eachof the respective base stations 104. The signal can also travel theother way, from base station to mobile terminal. In another exampleposition can be determined based on signal strength relative to one ormore known cells or base stations 104. The detection could be performedby the cellular positioning system 113 running on the user terminal 102itself, or could be performed by another network element such ascontroller station 105 and then signalled to the positioning system 113running on the user terminal 102.

Another option is that the positioning system comprises code configuredto detect the position of the respective user terminal 102 by referenceto the location of one or more of the WLAN access points 106. This maybe achieved by detecting an identifier (ID) of one or more access points106. Either the ID of the access point 106 could be mapped to a knownlocation of the access point, or the ID itself could be used directly asan indication of geographic location.

In the case of detecting the location by reference to one or more basestations 104 or to a wireless access point 106, the positioningcalculation (e.g. the trilateration) may be taken care of on a hostterminal of the respective network 103 or 101 (e.g. on a cellularcontroller station 105 or a server in communication with the wirelessaccess point 106). The positioning system on the user terminal 102 wouldthen comprise a suitable programming interface for retrieving thelocation information from the host terminal. However, anotherpossibility is for the user terminal 102 performing its own positioningcalculation by reference to the one or more base stations 104 orwireless access point 106 is not excluded, e.g. by performing its owncell trilateration.

Other methods also exist. For example, the location of a mobile phonecan be calculated by comparing a multipath signal pattern received by abase station with prior known information stored in a database throughpattern matching algorithms known as fingerprinting.

Whatever form the positioning system 113 takes, in embodiments it isconfigured to detect the geographical location of its own respectiveuser terminal 102. That is to say, by means of a measurement ordetermination process that is at least partially automated, rather thanlocation information simply being entered manually at the respectiveuser terminal 102 for example. However, the option of a manually enteredlocation is not excluded.

Further, the processing apparatus 112 on the mobile terminal 102 will bearranged to perform scanning processes via its local transceiver 115 andcellular transceiver 114, to scan for availability of WLANs and the WWANrespectively. This means the communication client application running onthe processing apparatus 112 can be kept aware of what networks areavailable for internet access, and hence select one of the WLANs orselect between a WLAN and WWAN as a means for accessing the internet101, e.g. for performing a real-time VoIP call with another userterminal 102 over the internet 101. Other examples are to view a websiteor send an email via a server of the internet 101, or send or receive anIM message or file transfer to or from another user 102. In embodimentsthe scanning process may be used to enable handover during an ongoingcommunication, e.g. to handover mid call or during a file transfer.

To assist in the scanning and handover process, there is provided adatabase of the kind shown by way of example in FIG. 2, 3 or 4.

The database may be stored and maintained in a server 108 connected toone of the networks such as the internet 101, allowing it to be accessedby the mobile terminal 102 via the current transceiver 114 or 115 andcorresponding one of the WWAN or WLANs by which it is currentlyconnected to the internet 101. Alternatively the database may be storedand maintained in a memory (e.g. 110) of the mobile terminal 102 itself.

The database provides a look-up table listing a relevant geographicallocation against each of a plurality of networks or their individualaccess points or base stations. In conjunction, the database also listsrespective tags providing additional information for use in controllingthe scanning and/or handover process. The tags can be allocateddynamically by the users themselves, i.e. based on their experience ofthe networks.

In some embodiments, the database is configured so as to provide alook-up table listing measures of connection quality for the differentpossible WLANs against corresponding geographical locations relevant tothe respective connection quality. Notably, some or all of the measuresof connection quality are contributed by the mobile user terminal 102itself based on its own past experience, or communally by a plurality ofuser terminals 102, rather than being centrally maintained by a networkoperator or at least rather than being maintained purely by theoperator. The corresponding geographical locations may comprise eitherthe locations of the WLAN access points, or the locations of the mobileterminal 102 at the time of recording its experience.

Note that the term database as used herein does not imply any particularsize or amount of data, and nor does the term look-up table imply agraphical table nor any particular structure or layout other than theability to look-up element against another associated element.

In the example of FIG. 2, each entry in the database comprises: anidentifier (ID) of a respective WLAN, an indication of location at whichthe mobile terminal encountered the respective WLAN, and at least onedynamically allocated “tag” providing additional information relating tothe experience of a mobile terminal 102.

In one or more embodiment, the one or more tags for each entry comprisea measure of connection quality which the mobile terminal 102experienced when it connected to the WLAN in question. The term qualitymay be used herein to refer to either fidelity and/or reliability.Fidelity is a measure of a property such as the bandwidth or signalstrength available on a particular connection. Reliability is a measureof a property such as how often a connection fails, or the amount oftime the connection is available (a connection could be high fidelitywhen it is available, but not be available very often, or vice versa).Quality may also refer to properties such as latency, loss and/orjitter. In an embodiment, quality is an aggregation of latency,bandwidth, reliability, loss and jitter. Alternatively the quality maycomprise any or all of these properties.

The processing apparatus 112 may be provided with a suitable algorithmfor making measurements such as peak, average or typical uplink ordownlink bandwidth, connection strength, connection up-time ordown-time, latency, loss, jitter, or an aggregate measure or any or allof these.

When the client application running on the processing apparatus 112 ofthe mobile terminal finds itself connected to a particular WLAN or aparticular WLAN access point, it instigates a measurement of theconnection quality and logs it in the database in association with anindication of the geographical location relevant to that measurement. Inan embodiment this may be the geographical location at which the mobileterminal 102 took the measurement, as determined by the positioningsystem (e.g. GPS transceiver 113) of the mobile terminal 102 itself. Thegeographic information may comprise coordinates of the experience, e.g.in the form of a latitude and longitude.

In this type of embodiment the client running on the processingapparatus 112 logs the self-determined location in the database alongwith the quality measurement. This is particularly advantageous as doesnot require a central operator to maintain the quality measures or thelocations in the database, both being contributed instead by the userterminal (or terminals). That is, it is not necessary for an operator orprovider to know about access points in advance. Instead it allows usersto discover them for themselves.

An alternative is for the geographical location in the database tocomprise a predetermined, known location of the access point 106 throughwhich the mobile terminal 102 connected. In this case the geographiclocations of the access points 106 may be provided by one or morenetwork operators as predefined elements in the table, against which theclient on the mobile terminal 102 logs its measurements. In this casethe mobile terminal does not need to submit location measurements aspart of the logging process, although it does place a burden on theoperator.

Either way, the measurement may be instigated in a number of ways. Forexample the client application on the mobile terminal 102 may make andlog the measurement at the time when it first encounters a new networkor first makes a new connection, or at a time of experiencing a peak,average or typical connection quality within a given time window orevent (e.g. during a call), or based on a random or periodic timing.

Optionally, the database may also include entries for one or more WWANs,e.g. an entry for each of a plurality of cellular WWAN base stations orcells 104, or an entry for one or more satellite networks. These entriesmay again be supplemented with dynamically allocated tags, comprisingexperienced connection quality which may be logged by one or more mobileterminals 102, either recorded against predetermined known locations ofthe base stations 104 or against the location of the experience asdetermined by the positioning system of the mobile terminal 102 at thetime. The manner of logging the information on the WWAN(s) need not bethe same as used in relation to the WLANs, though it may be.

In embodiments, each mobile user terminal may maintain its own personaldatabase on a storage medium (e.g. memory 110) of the mobile terminal102 itself.

Alternatively, in an even more advantageous embodiment, a plurality oflike client applications running on a plurality of mobile terminals 102are arranged to contribute to a combined database. The combined databasemay be stored on a server 108 connected to one of the networks to whichthe mobile terminals have common access, e.g. the internet 101.Alternatively the combined database could be created by sharing recordedexperiences between mobile terminals 102 (e.g. using an ad-hoc orpeer-to-peer network), in which case each mobile terminal 102 stores itsown instance of the combined database in local storage (e.g. 110).

In the case of a combined database, the amount of data is liable to growvery large, making it unwieldy to search. Even in the case of apersonal, local database maintained by one mobile terminal 102 for itsown use, the database may nonetheless become cumbersome as many resultsare logged over time. Therefore there is provided a method ofcompressing the data into a more manageable form. One way to do this isto detect areas with a high density of entries for a particular WLAN orparticular WLAN access point 106, and input these points into anaveraging or combining function in order to produce a centroid. Thisfunction may be applied by the client application running on the mobileterminal 102 or by a suitable function implemented on the server 108, asappropriate to the embodiment in question. The data could also betrained over multiple iterations, i.e. so that a plurality ofalready-averaged centroids become the input data to a further averagingfunction to create a second generation centroid, and so forth.

Note that FIG. 2 does not represent the only way of storing localizationdata. Some other examples are provided in FIGS. 3 and 4.

In the example of FIG. 3, instead of network IDs each entry is listed byan identification of an individual connection point of the network inquestion: i.e. either an access point 106 of a WLAN or a specific cellor base station 104 of the WWAN. This is shown schematically in themiddle column of FIG. 3. In this case the geographic location associatedwith each entry need not necessarily be the location of the mobileterminal 102 when it logged its experience (though that is still oneoption). Instead, the geographic location may be a predeterminedlocation of the connection point (access point or base station),pre-stored in the database by the operator or operators of the networkor networks in question. This embodiment may be more suited to adatabase maintained centrally on a server 108 rather than on individualmobile terminals 102, though it is not excluded that the operatorprovides information on locations of access points and/or base stationsto the mobile terminals 102.

Of course in many cases, where the WLAN comprises only one access point106, the identification of the WLAN access point 106 may be the same asor equivalent to the ID of the WLAN.

Furthermore, the geographic location need not be defined in terms of thecoordinates of a specific point or only in such terms. The geographicinformation may alternatively or additionally define a region, i.e. anarea. This is shown schematically in the left-hand column of FIGS. 3 and4.

For example, in FIG. 3 optional additional information may be includedalong with the coordinates of the connection point indicating an extentof the coverage from that point, e.g. an approximate radius to which thecoverage extends from the connection point.

In the example of FIG. 4, the geographic information is defined in termsof a region associated with a particular respective network ID. E.g.this information may comprise the name or an indication of a particulartown or area, or the coordinates of a set of connection points (WLANaccess points or WWAN base stations as appropriate), or a geometricdefinition of a region such as polygon on the earth's surface (e.g.defined in terms of the vertices of the region).

Once the table begins to be compiled, it can be used by the clientapplication running on the processing apparatus 112 of a mobile terminal102 to determine whether or when to scan for the availability ofalternative access networks (WLAN or WWANs) for accessing the internet101, with a view to potentially handing over between access networks.For example, the database can be used to determine whether a mobileterminal 102 currently connected to the internet 101 via a WWAN such asa 3G mobile cellular network should scan for availability of a WLAN suchas a wi-fi network, so as to potentially handover to the WLAN. Or thedatabase may be used to determine whether a mobile terminal 102currently connected to the internet 101 via a WLAN should scan for theavailability of an alternative WLAN, so as to potentially hand over tothe alternative WLAN. As mentioned, this could be used to handoverduring a VoIP call or other internet communication such as an IM chatsession or file transfer.

The client running on the processing apparatus 112 of the mobileterminal 102 is configured to access the database, e.g. from theterminal's own local storage 110, or from server 108 via its currentconnection to the internet 101. The client running on the mobileterminal 102 then determines its own current geographic location usingits positioning module, e.g. GPS 113, and uses its current location toindex the database by geographic location. The mobile terminal 102 isthereby able to find the entry most relevant to its current location.

The database may be structured to enable the client on the mobileterminal 102 to narrow down the entries before searching by geographicinformation. For example, the database may comprise a tree structure,e.g. ordered by country, and then region inside each country, andpotentially further subdivisions of region. E.g. the database maycomprise a global table of entries, divided into sub tables for eachcountry, then the sub-table for each region may be sub-divided into afurther level of sub-table for each smaller region within that region,and so forth as required to achieve a practically searchable level ofsub-table. If the client on the mobile terminal 102 has a high-levelindication of its region (e.g. knows that it is connected in the UK, orin south west London, or a particular borough in south west London) itcan then access the relevant sub-table in the database. However,searching a whole global table is not excluded (though it would be heavyon processing resources).

Within the relevant table or sub-table, the client on the mobileterminal 102 then indexes the remaining entries according to the mobileterminal's own current geographical location. For example it maycalculate the distance of the mobile terminal 102 from the geographiclocation of each entry in the sub-table (e.g. in the examples of FIGS. 2and 3) and select the most relevant (e.g. closest). Alternatively it maydetermine the relative location in terms of which geographically definedregion or regions the mobile terminal currently falls within (FIG. 4).

In one embodiment, the client on the mobile terminal 102 indexes thetable or sub-table according to distance or relative geographiclocation, and for those within suitable range determines the associatedmeasure of connection quality found in the look-up table provided by thedatabase. The client running on the processing apparatus 112 of themobile terminal 102 thus determines the best result, i.e. best qualitywithin range according to the table.

An alternative is for locations in the table to be quantized accordingto a structured, cell-like grid, as will be discussed later in relationto FIGS. 5 and 6. In this case the client looks up the availablenetwork(s) in the current unit area of the grid in which the mobileterminal currently finds itself.

The client application on the mobile terminal 102 may be configured toperform the table look-up to assess network availability on a periodicor random basis, or in response to being to a certain event such asdetecting that current connection quality has fallen below a certainthreshold. In another alternative, the results could be looked-up andprovided to the mobile terminal 102 by a network element such as thesever 108, via the access point or base station through which the mobileterminal 102 is currently connected to the internet 101.

Once the table is accessed and indexed to find the most appropriateentry, this result may then be used by the client on the mobile terminal102 to decide whether it is worth powering up its transceiver(s) toperform a scan for other available potentially networks (other than theone it is currently connected to). This may comprise deciding whether toinitiate a handover process. In embodiments, initiating a handoverprocess comprises at least as an initial stage performing a scan (asopposed to conventional systems which perform a periodic scan). Oncondition that the scan detects empirically that the network expectedbased on the table look-up is indeed available, the mobile terminal 102then hands over.

So if the best entry as determined according to the table look-upcorresponds to a different network than that which the mobile 102 iscurrently using to connect to the internet 101, the client applicationinitiates a handover by first performing a scan to test whether the newnetwork is actually present, and then if so handing over to thatnetwork. For example if the mobile terminal is currently connected tothe internet 101 by a WWAN such as a 3G cellular network, but the bestentry found in the table based on relative location and connectionquality corresponds to a particular WLAN such as a wi-fi network, thenthe mobile terminal 102 is configured to use the ID of that WLAN asindicated in the relevant table entry to initiate a handover process.This starts with at least a scan to test whether the expected WLAN isreally available, and if so continues to complete the handover. If itturns out the WLAN is not in fact available on the other hand (e.g.because it is experiencing a temporary problem or the table is out ofdate) then handover may be aborted, or the second best entry could betried.

Similarly, if the mobile terminal is currently connected to the internet101 by a WLAN such as wi-fi network, but the best entry found in thetable based on relative location and connection quality corresponds to adifferent WLAN such as another wi-fi network, then the mobile terminal102 is configured to use the ID of the new WLAN as indicated in therelevant table entry to initiate a handover process. This starts with atleast a scan to test whether the expected new WLAN is really available,and if so continues to complete the handover. If it turns out the newWLAN is not in fact available on the other hand then handover isaborted, or the second best entry could be tried.

In alternative embodiments, the mobile terminal 102 may be configured toperform a periodic scan, and the results from the table look-up may beused to adapt the frequency of scanning or to inhibit the periodic scan.For example, if it is determined that there are no likely bettercandidates at the mobile terminal's current location, the scan may beperformed at lower rate or regularity (fewer scans per unit time); butif it is determined that likely better candidates do appear to beavailable based on the table-took up, it increases the scans to a highrate or regularity (more scans per unit time). In another example, themobile terminal may be configured to perform scans periodically, but tocancel one or more of the scheduled scans if it is determined based onthe table look up that no better candidates are likely to be availableat the mobile terminal's current location.

Instead of searching the table for the best quality network from amongsta plurality within suitable range, a variant of this is to index thetable by location to find the closest network to the mobile terminal,then check whether that closest network promises a better connectionquality than the current network according to the associated tag in thelook-up table.

Note that the table does not necessarily comprise entries for all typesof network. E.g. in one embodiment the table only comprises entries forWLANs or WLAN access points 106, but not WWANs or WWAN base stations orcells (e.g. not for 3G mobile networks or satellite back-up networks).In this case one or more WWANs may be assumed always to be present. Inembodiments, the decision whether to scan and attempt handover from aWWAN to a WLAN may be based on whether the best WLAN entry found in thetable passes a certain threshold or other criterion—for example if themetric is below a certain threshold if the metric increases withdistance and decreases with quality, or above a certain threshold if themetric decreases with distance and increases with quality. If thethreshold or criterion is not met, the mobile terminal 102 may connectto the internet 101 via a particular WWAN by default, e.g. via a cell104 and control station 105 of the 3G cellular network 103.

Quality measurements are not the only kind of additional informationwith which entries in the table may be tagged.

Other information with which entries may be tagged includes motioninformation, which information may comprise an indication of whether theconnection point of a network is stationary or moving, and/or a measureof speed or velocity of the connection points. This is particularlysuited to a situation in which each entry of the table comprises anelement identifying an individual connection point and/or a particularWLAN. For example, nowadays WLANs are increasingly found on publictransport such as trains, busses, planes and boats, or even in privatecars.

The motion of the WLAN may be relevant to the decision as to whether itis worth spending battery power scanning, and whether it would bedesirable to handover. For example, a WLAN on a passing train will notbe very useful to a user who is relatively stationary. On the otherhand, a user on the train is likely to want mainly to use the train'sWLAN, and other passing WLANs that are relatively stationary on theground will be not tend to be useful.

The motion information for each of a plurality of the entries in thetable may comprise an indication as to whether or not the access pointor WLAN is moving. Alternatively or additionally, the motion informationfor each of a plurality of the entries in the table may comprise anindication of speed (magnitude only) or velocity (magnitude anddirection), or indeed just direction. Direction may matter, e.g. amobile terminal 102 moving at a similar speed as a WLAN and inapproximately the same direction may have reason to connect to it, but amobile terminal 102 moving at similar speed but substantially oppositedirection to a particular WLAN would probably not want to connect tothat WLAN.

In embodiments, the motion information is captured and taggeddynamically by one or more individual mobile terminals 102 based ontheir own experience, in an analogous manner as described in relation tothe quality information.

In this case, instead of measuring connection quality, the clientapplication on the mobile terminal 102 determines an indication ofmotion as and when it encounters a given network. For example, themotion measurement could be determined by detecting how quickly theaccess points or cells or base stations pass by relative to the mobileterminal 102, and/or Doppler estimates based on signals from accesspoints or cells or base stations may be used. Information from one ormore accelerometers (not shown) and/or GPS on the mobile terminal 102may also be taken into account (so that the mobile 102 knows it is notitself the one moving, if so how much of the relative motion is due toitself). In embodiments, multiple such factors can be taken into accountto give an estimation of the motion of the WLAN or its individual accesspoints 106. The measurements may be instigated and logged in any of thesame ways discussed in relation to the quality information.

However, another option is for some or all of the motion information tobe maintained in a predetermined fashion by one or more operators,and/or entered manually by a user based on experience.

In some embodiments the motion information may be taken into account ina combined metric, combining quality and motion information.Metric=function{quality,relative motion}

The table can then be used to find a best (most relevant) entry for themobile terminal according to this combined metric at its currentlocation, in a similar manner to that described above but with themetric also taking into the mobile's own state of motion relative to theentries in the table, e.g. whether the mobile terminal 102 itself ismoving or not and/or its own speed or velocity). The particular form ofthe metric is free for the system designer to tune according toparticular requirements, e.g. based on simulations of the particularcommunication system in which it is to be applied.

Alternatively, instead of searching the table for the best entry withinrange according to the combined metric, the client on the mobileterminal 102 may look-up the closest access network that is not ruledout by a particular rule, such as that all moving WLANs are to beignored unless moving in the same direction as the mobile terminal 102(within some allowed margin).

Once the desired entry is found, the client running on the mobileterminal 102 determines whether this corresponds to a different accessnetwork than the mobile is currently using to connect to the internet101, and if so control scanning and potentially handover. Again, theprocess may proceed in the same manner described in relation to thescanning and handover based on the quality tags.

In embodiments, the table may contain both motion information andgeographical location. Either or both of these may be tagged dynamicallyby a mobile terminal as and when it experiences the network. Of courseif an access point is moving, e.g. because it's installed on a train, itmay not have a well-defined location. There are a number of ways tocombine both motion information and geographic information into the sametable for use in predicting network availability.

On way is for stationary networks or access points to be tagged with astatic geographic location, and for moving networks or access points tobe tagged with motion information indicative of motion instead of thegeographic location. These different kinds of information may beincluded for different entries in the same table. I.e. each entrycomprises one bur not both of: a geographic location (and optionallymotion information in the form of a flag indicating that the network oraccess point is stationary), or motion information indicative of motion(either in the form of a flag indication motion and/or an indication ofthe speed, direction or velocity of the network or its access point(s)).

For example, the server 108 may be configured to recognize when it hasreceived a lot of contradictory localization observations. From that,the server may tag the network as “moving”—so it yields dynamic“movement” tagging. That also means that the observation of that accesspoint is not useful for positioning. The relevancy of a moving accesspoint depends on the mobile terminal moving itself

In a more advanced implementation, the system may exploit knowledge thatthe mobile terminal's position is somewhere on a line or route overwhich the access point has been observed. For example, the database maybe configured to map the multiple observed positions of the access pointalong a regular route like a train line. The client on the mobileterminal 102 may then be configured to determine that when it is foundat a geographic location along the train line or other such regularroute, then there is a possibility of the access point or network beingavailable. In this embodiment, a given entry in the table may includeboth geographic location information and motion information.

Another way is to tag the access as being available at a particularlocation at a particular time of day, e.g. based on train time tables orreal-time updates available from railway operators. See also discussionlater on including time of day in the look-up table.

Further, according to one embodiment, each of a plurality of entries inthe database is also tagged with price information. This information maycomprise a quantitative indication of the actual cost of connecting tothe internet 101 through a particular access network, or just anindication of whether the network or access point is free or not. Forexample, some WLANs are free whilst some others incur a cost, e.g. acost per unit time. The cost of different WLANs may also be different.Alternatively or additionally, the table could include the cost of oneor more WWANs, e.g. 3G cellular network and/or satellite back-upnetwork.

In one embodiment, the price information is tagged dynamically by usersthemselves, in a similar manner as described in relation to the qualityinformation and motion information, i.e. based on their actualexperience when encountering networks rather than the price databasebeing centrally administered by one or more operators. The informationcould be logged automatically by the client application, or manuallyinstigated by the user. This advantageously enables users to rateproviders in a “virtual marketplace”.

As an extension to the globally tagged access points, the client runningon the mobile terminal 102 may present the user with his currentconnection options including quality indicators, along with pricinginformation to help him select an appropriate one. Alternatively, theclient application may make the decision for the user based on thepricing information and what he or she is doing at the time (e.g. audioor video call), using a selection policy which can be either a defaultone or one defined or selected by the user.

The table is initially indexed according to geographic location. Insteadof just automatically selecting the best entry based on quality and/ormotion and performing a scan in dependence on that entry, the clientapplication on the mobile terminal 102 may be configured to generate ashort-list from amongst a plurality of best entries according to thegeographical locations, quality information or combined metric. Theclient then displays the short-list to the user, with price listedagainst network. In embodiments, the short-list also displays othertagged information such as the connection quality and or motioninformation alongside the identity of the networks. The user is thenable to select one of the access networks, e.g. to select between WWANand WLAN and/or select between multiple available WLANs.

For example the user wishes to perform a non real-time communicationsuch as a file transfer and is not in a hurry, he or she may choose acheaper but worse quality network, e.g. a free WLAN that is slow becauseit is shared between many users. On the other hand if the user wishes toperform a real-time or urgent communication such as a VoIP call, he orshe may choose a more expensive but faster or more reliable network suchas a paid WLAN or a WWAN.

Alternatively the client application may not necessarily display theshort-list to the user, but may be configured to automatically selectone of the access networks from the short-list according to theautomatic selection policy (e.g. select the best quality candidate forreal-time calls and the cheapest candidate for non real-timecommunications).

Thus the user is presented with a list of available networks along withtheir quality as experienced by other users, or alternatively, a networkis selected for the user based on pricing information, quality, and userneeds/activity.

In another alternative, the price information may be taken into accountin a combined metric, e.g. as a function of {quality, motion, price},and the client application running on the mobile terminal 102 may usethis metric to automatically select the best entry from amongst thosewithin suitable range based on the indexed localization. For example ifthe best entry does not correspond to the current network (e.g. thetable look-up indicates there is a better WLAN available when price isweighed against connection quality), then the client application maytrigger a scan and potentially a handover in the same manner discussedabove in relation to the quality and motion information.

Other information listed could include time of day. For example, certainnetworks may be more or less likely to be available at certain times ofday.

The information on time of day may be logged in any of the same waysdiscussed in relation to the quality tags, e.g. dynamically by themobile terminal 102. In embodiments, the time-of-day may be used as anextra table index, i.e. the table may be indexed based not only ongeographic location, but also based on time of day. So the searching ofthe table does not just comprise checking a certain network at a certainlocation, but also checking a certain network at a certain time of day.For example, some networks may be fine mid-day, but horrible in rushhour. E.g. this may be the case with the 3G network in the businesscentre of a busy city due to commuters with smartphones.

A method using a database of a kind exemplified in relation to FIG. 2, 3or 4 may proceed as follows.

-   -   (i) Obtain the position of the mobile terminal (MT) by GPS, base        station trilateration, or WWAN/WLAN ID (using WWAN and/or WLAN        ID requires the server knows the relevant positions). If the        user terminal knows the position by GPS, it may send coordinates        to the server along with WLAN/WWAN ID so the server can add the        ID to its table.    -   (ii) Poll a server (or a locally maintained or shared        distributed database) for list of nearby networks (according to        some suitable proximity criterion), and look up the associated        tags such as quality, motion and/or price information.    -   (iii) If multiple tags are taken into account, e.g. quality and        motion, compute a score for each network determined to be nearby        according to the table. For example, score=f(quality, motion).    -   (iv) If there is a better network, scan for it.    -   (v) Handover to network with best score.    -   (vi) After use, send the experienced quality to server so it can        update its quality for the network. The database is thereby        dynamically maintained. Alternatively or additionally the table        could be dynamically updated on other occasions, e.g.        periodically or upon a certain event such as entering a new        network for the first time.

An alternative method using an alternative kind of database is nowdiscussed in relation to FIGS. 5 and 6.

Referring to FIG. 5, in this alternative method a geographical regionsuch as a country or region of the globe is considered to be divided andsub-divided into areas and sub-areas, into multiple hierarchical levelsof sub-area. As shown in the left-hand columns of FIG. 6, each of aplurality of entries in the table then corresponds to a respective unitof geographical area, a unit being the smallest level of sub-area, i.e.smallest sub-division. Thus the region is divided into a cell-like grid(not necessarily square or rectangular), but each “cell” corresponds toa geographical sub-division on the map, rather than the area covered bya particular access point or base station.

The database then provides a look-up table (maintained on a server 108or on the mobile terminal 102 itself) which maps against each cell-likegeographic unit a list of any networks that have been found to beavailable in that unit (i.e. sub-area). This is shown schematically inthe middle column of FIG. 6.

In addition, the table stores the associated tags (quality, motionand/or cost information) for each of the networks. In FIG. 6 the tagsare mapped against each occurrence of each network in each unit.Duplicate entries can be avoided by averaging quality tags for the{location,network} tuples.

In embodiments, the tags are again logged dynamically by the mobileterminal 102 or a plurality of such mobile terminals as and when theyencounter the relevant experience, along with in identification of thegeographical unit in which they encountered that experience.

The mobile terminal 102 can thus access and index the table by location,to determine the identities of nearby networks and associatedinformation such as quality, motion and/or cost. The different levels ofdivision and sub-division make the table more efficient for the mobileterminal to search. Such a method may proceed as follows.

-   -   (i) Obtain position of Mobile Terminal (MT) by GPS, base station        trilateration, or WWAN/WLAN ID. For WWAN/WLAN positioning, the        server keeps a table indexed WWAN/WLAN ID containing an estimate        of their position. If the user terminal knows its position by        GPS, this is sent to server along with WWAN/WLAN ID. The server        uses this to update its WWAN/WLAN position estimate.    -   (ii) The server holds a table indexed by geographical positions        that is a cell-like, world-spanning grid. Cells can be smaller        than WWAN cells. The table may be huge, but well-structured so        easy to search.    -   (iii) Server keeps a list of networks known within each cell.    -   (iv) For each network in a cell, keep track of experienced        quality.    -   (v) The mobile terminal scans for a better network if the server        table indicates a better one should be available.    -   (vi) The mobile terminal hands over if better network is        available.    -   (vii) After use, the mobile terminal sends its experience to        server to update its quality of network in given position.

The cell-like structure provides an alternative way of the mobileterminal 102 logging its position. Instead of the actual coordinates atwhich the mobile terminal encountered the logged experience (quality,motion or price information), or an average centroid based on multiplemobile terminals experiences; an identification of the geographical unitcorresponding to the sub-area in which the mobile terminal 102encountered the experience can be logged.

Either way, an advantage of the mobile terminal logging its position isthat the server does not need a priori knowledge about WWAN and/or WLANpositions, but can update these dynamically too. A potentialdisadvantage is that distance to the access point may not be taken intoaccount explicitly without such knowledge. A way to mitigate this is instep (vi) is to take into account signal strength when deciding whichnetwork is better (signal strength is known after scan).

It will be appreciated that the above embodiments have been describedonly by way of example.

For example in embodiments, the wireless local area networks maycomprises at least one of a wi-fi network, a HiperLAN network, a HomeRFnetwork, an OpenAir network and a Bluetooth network, or others.

The one or more wireless wide area networks may comprise one or more ofan LTE, W-CDMA, GSM, UMTS, UTRAN, HSPA, CDMA2000 or other 3GPP network,a WiMAX network, a CDPD network and a Mobitex network, or others.Alternatively or additionally, the one or more wireless wide areanetworks may comprise a satellite network.

The first network may be the internet, or other packet-based network.

The processing apparatus may be configured to estimate, based on saiddatabase, whether a better quality is likely to be available on one ofsaid connections at the geographic location of said mobile terminal asdetermined by said positioning module, relative to a current one of theconnections formed by the processing apparatus; and the processingapparatus may be configured such that said control comprises: triggeringan instance of the scan if it is estimated that a quality connection islikely to be available, and/or inhibiting a scheduled instance of thescan if it is estimated that no better quality connections are likely tobe available.

Alternatively the processing apparatus may be configured to estimate,based on said database, whether a better quality is likely to beavailable on one of said connections at the geographic location of saidmobile terminal as determined by said positioning module, relative to acurrent one of the connections formed by the processing apparatus; andthe processing apparatus may be configured such that said controlcomprises: reducing a number of instances of the scan per unit time ifit is estimated that no better quality connections are likely to beavailable, and/or increasing a number of instances of the scan if itappears from said that a better connection is likely to be available

The database may be stored at a server and populated by measurementsfrom a plurality of user terminals including said mobile terminal.

Alternatively, the database is stored at said mobile terminal andpopulated by said mobile terminal.

The positioning module may be arranged to determine the location of theusing one or more of: GPS, identification of one or more access pointsof the wireless local area networks, an identification of one or morecells of a wireless wide area network, a trilateration between ones ofsaid access points and/or base stations, a measure of signal strengthrelative to one or more of said access points and/or base stations, anda comparison of a multipath signal pattern received by a base stationwith prior known information, or others.

In embodiments the database may comprise additional information relatingto a price of one or more access points of the wireless local areanetworks; and the processing apparatus may be configured to controlactivation of the local transceiver to perform the scan in furtherdependence on the price of one or more of the access points.

In further embodiments, the processing apparatus may be configured tocontrol activation of the local transceiver to perform the scan infurther dependence on motion of the mobile terminal, and the motion maybe determined using one of: the positioning module, and one or moreaccelerometers of the mobile terminal, or others.

Other variants may become apparent to a person skilled in the art giventhe disclosure herein. The scope of the claimed subject matter is notlimited by the described examples but only by the accompanying claims.

The invention claimed is:
 1. A mobile terminal for use in acommunication system comprising a packet-based network and a pluralityof wireless local area networks providing access to the packet-basednetwork, the mobile terminal comprising: a positioning module arrangedto determine a geographical location of the mobile terminal; a localtransceiver for connecting to the wireless local area networks; andprocessing apparatus coupled to the local transceiver and positioningsystem, operable to communicate with the packet-based network by formingconnections with the wireless local area networks using the localtransceiver, the processing apparatus configured to: control activationof the local transceiver to scan for subsequent availability of one ormore of the wireless local area networks, in dependence on one or moremeasures of connection quality and associated geographical locations ina database relative to the geographical location of the mobile terminalas determined by the positioning module; select a wireless local areanetwork from the one or more wireless local area networks based on priceinformation associated with individual ones of the one or more wirelessnetworks; and determine measures of connection quality experienced bythe mobile terminal on one or more of the connections and record thedetermined measures in the database, associating the determined measuresof connection quality with one or more geographical locations.
 2. Themobile terminal of claim 1, the communication system further comprisingone or more wireless wide area networks providing access to thepacket-based network, and the mobile terminal comprises a furthertransceiver for connecting to one or more of the wireless wide areanetworks, the processing apparatus being coupled to the furthertransceiver and operable to communicate with the packet-based network byforming a connection with one or more of the wireless wide area networksusing the further transceiver.
 3. The mobile terminal of claim 2, theprocessing apparatus further configured to select whether to connect tothe packet-based network via one of the wireless wide area networks orone of the wireless local area networks based on one or more of measuresof connection quality associated with individual ones of the wirelesslocal area networks and wireless wide area networks.
 4. The mobileterminal of claim 2, the processing apparatus further configured toselect whether to connect to the packet-based network via one of thewireless wide area networks or one of the wireless local area networksbased on price information associated with individual ones of thewireless local area networks and wireless wide area networks.
 5. Themobile terminal of claim 1, wherein the geographical locations in thedatabase comprise locations measured by multiple mobile terminals, theprocessing apparatus further configured to dynamically record ageographical position of the mobile terminal and one or more measures ofconnection quality when determining the geographical location.
 6. Themobile terminal of claim 2, wherein during an ongoing communication withthe packet-based network using a current one of the connections, theprocessing apparatus is further configured to switch the ongoingcommunication from the current one of the connections to a different oneof the connections using one of the wireless local area networks orwireless wide area networks.
 7. The mobile terminal of claim 2, theprocessing apparatus further configured to use one or more of theconnections to conduct a live packet-based video or voice call over thepacket-based network and, while the call is ongoing, switch the callfrom the current connection to a different one of the connections usingone of the wireless local area networks or wireless wide area networks.8. The mobile terminal of claim 1, the database comprising additionalinformation relating to motion of one or more access points, theprocessing apparatus further configured to control activation of thelocal transceiver to perform the scan in further dependence on themotion of one or more access points.
 9. The mobile terminal of claim 1,the processing apparatus further configured to suspend scanningresponsive to detecting that the mobile terminal is moving.
 10. Themobile terminal of claim 9, the processing apparatus further configuredto resume scanning, following the suspension of the scanning, responsiveto determining that the mobile terminal is no longer moving.
 11. Themobile terminal of claim 1, the processing apparatus further configuredto reduce a number of instances of the scan per unit time based at leastin part on motion of the mobile terminal.
 12. A mobile terminal for usein a communication system comprising a packet-based network and aplurality of wireless local area networks providing access to thepacket-based network, the mobile terminal comprising: a positioningmodule arranged to determine a geographical location of the mobileterminal; a local transceiver for connecting to the wireless local areanetworks; and processing apparatus coupled to the local transceiver andpositioning system, operable to communicate with the packet-basednetwork by forming connections with the wireless local area networksusing the local transceiver, the processing apparatus configured to:control activation of the local transceiver to scan for subsequentavailability of one or more of the wireless local area networks, independence on one or more measures of connection quality and associatedgeographical locations in a database relative to the geographicallocation of the mobile terminal as determined by the positioning module,the geographical locations in the database comprising locations measuredby multiple mobile terminals; select a wireless local area network fromthe one or more wireless local area networks based on a time of day; andrecord the geographical location of the mobile terminal and one or moremeasures of connection quality in the database.
 13. The mobile terminalof claim 12, wherein each of the measures of connection qualitycomprises a measure of one or more of latency, bandwidth, reliability,loss or jitter.
 14. The mobile terminal of claim 12, the communicationsystem further comprising one or more wireless wide area networksproviding access to the packet-based network, the mobile terminalcomprising a further transceiver for connecting to one or more of thewireless wide area networks, the processing apparatus being coupled tothe further transceiver and operable to communicate with thepacket-based network by forming a connection with one or more of thewireless wide area networks using the further transceiver.
 15. Themobile terminal of claim 12, the processing apparatus further configuredto use one or more of said connections to conduct a live packed-basedvoice or video call over the packet-based network.
 16. The mobileterminal of claim 12, the processing apparatus further configured tosuspend scanning responsive to detecting that the mobile terminal ismoving.
 17. The mobile terminal of claim 16, the processing apparatusfurther configured to resume scanning, following the suspension of thescanning, responsive to determining that the mobile terminal is nolonger moving.
 18. A method comprising: determining a currentgeographical location of a mobile terminal using a positioning system ofthe mobile terminal; communicating between a local transceiver of themobile terminal and a network by forming connections with one or morewireless local area networks; controlling activation of the localtransceiver to scan for subsequent availability of the one or morewireless local area networks in dependence on one or more measures ofconnection quality and associated geographical locations in a databaserelative to the current geographical location of the mobile terminal,the geographical locations in the database comprising locations measuredby multiple mobile terminals; selecting a wireless local area networkfrom the one or more wireless local area networks based on priceinformation associated with individual ones of the one or more wirelessnetworks and connecting to the selected network; and recording thegeographical location of the mobile terminal and one or more measures ofconnection quality in the database.
 19. The method of claim 18, whereinthe selecting is further based on a time of day.
 20. The method of claim18, wherein selecting a wireless local area network form the one or morewireless local area networks based on price information comprises:displaying one or more current connection options to a user of themobile terminal along with price information associated with individualones of the one or more connection options; and receiving a selectioninput indicating one of the one or more connection options, whereinselecting the wireless local area network is performed responsive toreceiving the selection input.